<!DOCTYPE html>
<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    h1 {
      color: red;
      font-size: 50px;
    }
  </style>
</head>

<body>
  <h1> 这是一个页面</h1>
  <h3>---------</h3>
</body>

</html>